Multiple-purpose rheostat



March 30 1926. 1,578,988

C. HARDY MULTIPLE PURPOSE RHEOSTAT Filed July 11, 1924 ATTORNEY Patented Mar. 30, 1926.

UNITED STATES PATENT OFFICE.

CHARLES HARDY, OF NEW YoRKpN. Y., ASSIGNOB TO AMSCO PRODUCTS, INC., OF NEW YORK, N. Y., A CORPORATION'OF NEW YORK.

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application filed July 11, 1924. Serial No. 725,361.

To all wlwm it may concern:

' Be it known that I, )CHARLES HARDY, a citizen of the United States, and a resident of New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Multiple-Purpose Rheostats, of which the following'is a specification.

My invention relates to multiple purpose rheostats, of the type in which a number of separate resistance elements are controllable independently of each other, for the purpose of varying the resistance in different circuits and thus regulating the current values of the different circuits.

An object of the invention is to produce a multiple purpose rheostat of compact iorm and simple construction, and made up essentially of a number of separate rheostats grouped compactly together, the different 'rheostats having separate knobs or equivalent handles whereby they may be con trolled independently of each other.

A further object is to provide simple .and efiicient means for insuring proper mechanical and electrical engagement between the several parts.

Other objects and aims of the invention,

more or less specific than those referred to above, will be in part obvious and in part pointed out in the course of the following description of the elements, combinations, arrangements of parts and applications of principles, constituting the invention, and the scope ofprotection contemplated will be indicated in the appended claims. In the accompanying drawings which are to be taken as a part of this specification, and in which I have shown merely a preferred form of embodiment of the invention:

Fig. 1 is a horizontal section through my multiple purpose rheostat, showing the same as mounted upon a supportlng panel, and

Fig. 2 is a front elevation of the multiple purpose rheostat and parts immediately associated therewith including a diagram matic illustration of a set. of circuits connected to be controlled by the present device.

A panel board 3 is used for supporting the various parts, and may be the wall of a radio cabinet, or of any other appropriate casing.

Extending through a hole in the panel board 3, and revoluble relatively to the panel board, is a metallic sleeve 4 of sub- .stantially cylindrical form, provided with a flange 5. This flange is integral with the sleeve 4, and thus is revoluble relatively to the panel board.

A body member 6, of substantially circular form, is mounted upon the panel board 3 by any suitable retaining means as for instance one or more bolts 7.

The body member 6 carries resistance strips 8 and 9. These resistance strips are each of arcuate form, and they are disposed concentrically to each other and to the circular body 6, as may be understood from Fig. :2. The strip 8 is of greater cross dian'ietcr than the strip 9, and may carry more current than the strip 9.

Mounted upon the body memberv 6 are binding posts 10, 11 and 12. While the number of resistance strips 8 and 9 and the number of the binding posts 10, 11 and 12 can be varied to suit requirements, I show in the present instance only two resistance slips and three binding posts. The strip 8 is connected with the binding post 10 and the strip 9 is connected with the binding post 11. The binding post 12 is for ground connection, that is it carries the opposite side of the circuit from posts 10 and 11. Secured rigidly upon the revoluble sleeve 4, and retained against displacement relatively thereto, as by a nut 14, is a contact arm 13 which extends radially outward and slidably engages the resistance strip 9.

Another contact arm 15 is mounted upon a set collar 16, the latter being secured rigidly upon a revoluble shaft 17 which extends through the sleeve 4. The outer end of the contact arm 15 rests upon and is slidable along the resistance strip 8.

' An operating knob 18, preferably of insulating material and having a tubular metallic core 19, is mounted upon the sleeve 4 and is held in position thereupon preferably by a set screw 20. The knob 18 is revoluble by hand, so that the operator, by turning it, rotates the sleeve 4 and thus actuates the contact arm 13.

A second operating knob 21 is mounted rigidly upon the outer end of the shaft 17, and is revoluble by hand for enabling the operator to rotate this shaft and so actuate the contact arm 15.

Thus the operator, by grasping and turning eitherof the knobs 18-or 21, can cause the rotation of the corresponding contact arm 13 or 15 independently of each other.

The resistance strip 8 is shown as being somewhat higher than the strip 9 so that the contact arm 15 can span directly over the 17- by means of a connecting link 12 which extends from saidbinding post 12 to a posi-l tion beneath the flange 5 of the sleeve. lhe spring pressure of the contact arm 13 against the resistance strip 9 tends always to move the sleeve longitudinally and thus produces a resilient pressure of the flange 5 against the underlying portion of link 22. spring pressure of the contact arm 15 against the resistance strip 8 also produces a continuous pressure of theshaft 16 laterally against the inner wall surface of the sleeve 4 and thus. provides a goodelectrical contactvbetween said shaft and sleeve. The knob 21 at the front end of the shaft 17 of course holds said shaft against longitudinal movement.

One or more appropriate electric circuits may be connected with my device by means of the binding posts '10, 11 and 12, and in Fig. 2 I show diagrammatically a very simple example of such circuits. A wire 23 is connected with the binding post 12 and with a battery 24. In metallic communication with this battery are two wires 25 and 26, leading to incandescent lamps 27 and 28 respectively adapted to be energized by currents from the battery 24. i

From the lamp 27 a wire 29 leads to the binding post 10, and from thelamp 28 a wire 7 30 leads to the binding post 11. Vacuum tubes or-any other appro riate ele-' ments may be substituted for t clamps 27 and 28.

The contact arm 13 is included in the circuit through the lamp 28, and the contact arm 15 is included in the circuit through the lamp 27.

With the apparatus thus arranged the operator, by turning the knob 21 and actuating-the contact arm 15, can regulate the current passing through the lamp. 27 and by turning the knob 18 and thus actuating the contact arm 13, he can control the cur.- rent throughthe lamp 28.

My multiple purpose rheostat is well adapted for radio work-such as the reception of broadcastedperformances, etc, In

The

this relation it may be used for controlling the various delicate circuits used, for instance in second stage audio and second stage radio frequency, or otherwise as may be desired.

In instances where onlytwo' circuits are construction Without departing from the scope of the invention as defined in the fol lowing claims, it is intended that all matter contained in the above description or shown in the'accompanying drawings, shall be in terpreted as illustrative only and not in a limiting sense.

I claim:

1. A multiple purpose rheostat comprising a body member of insulating material, a metallic sleeve extending through said body member and revolvable therein, an operating handle fixed to said sleeve at one side of the body member by which to rotate the sleeve, said sleeve having a shoulder thereon at said mentioned side of the body member facing toward the opposite side of the body member, a resistance strip carried by the body member at said opposite side thereof, a con tact arm carried by said sleeve arranged to sweep along said resistance strip by rotation of the sleeve, said contact arm being of spring material and being under tension exerting a pressurein a direction toward said first side of the body member against the resistance strip and a resultant pressure tending to move the sleeve longitudinally through thebodymember and thereby pressing the flangeof the sleeve toward said first side of the body member, a binding post carried by the body member, a conductor member extending from said binding post into position between the body member and the opposing surface of the flange of the sleeve to receive frictional cont-act therefrom during rotation of the sleeve, a second resistance strip carried by the body member at the same side of the body' member as said first resistance strip, a metallic shaft extending through the sleeve and revolvable therein, an operating handle fixed to the shaft beyond one end of the sleeve adjacent said first operating handle, a contact arm fixed to the shaft beyond the opposite end of the sleeve arranged to sweep along the second resistance strip upon rotation of. the -shaft, said second contact arm belng also of spring material andbeing under tension exerting a pressure toward the first mentioned side of the body member, against the second resistance strip and a re sultant pressure serving to hold the shaft laterally in tight rubbing contact with the inner surface of the sleeve whereby the mentioned binding post is electrically connected in common with both of said contact arms, and a pair of other binding posts carried by the body electrically connected with said resistance strips respectively.

2. A multiple purpose rheostat comprising a body member of insulating material having a bearing opening therethrough from its front to its rear surface and having an annular groove formed in its rear surface spaced concentrically from said bearing opening, a plurality of resistance strips arranged within said groove extending longitudinally along the groove and hence concentrically about said bearing opening, retaining means also within said groove arranged between said strips and serving to hold said strips spaced apart and to retain said strips against displacement from the groove, each of said strips having a longitudinally extending exposed surface portion thereof facing rearwardly outwardly of the groove, one of said resistance strips having its mentioned surface arranged relatively further rearwardly than the mentioned surface of another resistance strip, a plurality of operating members mounted to rotate within said bearing opening, a contact arm carried by one of said members arranged upon rotation of said member to sweep along the mentioned exposed surface of one of said resistance strips, ,and a further contact arm carried by another of said operating members projecting therefrom across said last mentioned resistance; strip-free thereof and arranged thereby to sweep along the mentioned exposed surface which is disposed rearwardly of the exposed surface of the last mentioned strip.

3. A multiple purpose rheostat comprising a body member of insulating material having a bearing opening therethrough from its front to its rear surface and having an annular groove formed in its rear surface spaced concentrically from said bearing opening, a pair of resistance strips arranged within said groove extending longitudinally along the groove and hence concentrically about said bearing opening, a retaining strip also within said groove arranged between said strips and serving to hold said strips spaced apart and pressed radially against the walls of the groove to thereby retain said strips against displacement from the groove, the groove being of uniform depth throughout, the resistance strips projecting rearwardly from said groove but being of different cross sectional dimensions so that one thereof projects further rearwardly from the groove than the other, the rear annular edge surfaces of said strips constituting contact surfaces and being thus disposed in different planes longitudinally of said bearing opening, a pair of operating members mounted to rotate within said bearing opening, a contact arm carried by one of said members arranged upon rotation of said member to sweep along the mentioned exposed .surface of one of said resistance strips, and a further contact arm carried by the other of said operating members projecting therefrom across said last mentioned resist? ance strip free thereof and arranged thereby to sweep along the contact surface of the resistance strip which projects farthest from the groove In testimony whereof I atiix my signature.

CHARLES HARDY. 

